Casement window mounted air conditioner



Oct. 4, 1955 T. J. DEERING CASEMENT WINDOW MOUNTED AIR CONDITIONER Filed Feb. 9, 1953 4 Sheets-Sheet l 7/ INVENTOR.

66 flmm diff/777g J MI Oct. 4, 1955 T. J. DEERING 2,719,410

CASEMENT WINDOW MOUNTED AIR CONDITIONER Filed Feb. 9, 1955 4 Sheets-Sheet 2 4 Sheets-Sheet INVENTDR. /o/mv fizz/W 7 O 1955 T. J. DEERING CASEMENT WINDOW MOUNTED AIR CONDITIONER Filed F013. 9, 1955 Oct. 4, 1955 Filed Feb. 9, 1953 T. J. DEERING v CASEMEINT wmoow MOUNTED AIR CONDITIONER 4 Sheets-Sheet 4 7 INVENTOR. flm/WZ/ 1766/ /77;

United States Patent CASEMENT WINDOW MOUNTED AIR CONDITIONER Thomas J. Deering, Cincinnati, Ohio Application February 9, 1953, Serial No. 335,798

8 Claims. (Cl. 62-129) This invention relates to an air conditioner of the type which may be mounted upon windows of the casement variety, as well as upon windows having sliding sashes. The casement window, of course, poses the most troublesome mounting problem in the installation of air conditioners of the type herein disclosed, which are commonly known as room coolers, or unit coolers.

An object of the invention is to provide a cooler or air conditioner of the character stated, which is particularly adapted for application to casement windows, or windows hung by means of vertical hinge pins, for swinging movement in a horizontal plane.

Another object is to simplify and expedite the installation of an air conditioner in a casement window structure,

thereby to effect substantial savings of time and labor, while at the same time avoiding mutilation and alteration of the structural elements of the window.

A further object of the invention is to obviate the necessity of removing or substituting window sashes in applying the air conditioner to casement windows.

Another object is to save time and labor in the event of moving the air conditioner from one casement window to another, When desirable, or in removing the device for repairs or replacement.

A further object is to provide a compact and simple form of air conditioning unit, so constructed that it will fit all known sizes and styles of casement windows, as well as all sizes of double-hung windows and variations there- .of.

Another object is to provide in a room air conditioning unit, the simplest of means to secure the unit to the window structure, without the drilling of holes, or the use of special frames, adapters or wings, which are not only expensive but unsightly as well.

A further object of the inventionis to construct an air conditioning unit with parts so designed and arranged as to reduce manufacturing and assembly costs to an extent heretofore believed impossible.

Another object is to provide for an effective and practical disposition of condensate, or water of condensation, from the unit.

The foregoing and other objects are attainedby the means described herein and illustrated upon the ,accompanying drawings, in which:

.densate, this constitutinga detailof the invention.

.Fig. is a side elevational view of the unit chassis, ,with .-all the. operating mechanism removed.

2,719,410 "Patented Oct. 4, 1955 Fig. 6 is an enlarged plan view of a mounting panel, constituting part of the chassis.

Fig. 7 is a perspective view of a modified form of the unit illustrated by Fig. 1.

Fig. 8 is a fragmentary perspective view of a typical casement window, conditioned for reception of the Fig. 7 unit.

Fig. 9 is a fragmentary cross-sectional view of a typical casement window construction, and showing in broken lines the mode of application of an air conditioning unit thereto.

Fig. 10 is a top plan view of the unit illustrated by Fig. 7, part being broken away to show the interior.

Fig. 11 is an enlarged perspective view ofpart of the chassis of the Fig. 10 unit, showing how the unit may be adjusted to fit various types of casement windows.

In the several drawing views, 12 indicates generally a casement window, the principal components of which are the glass panes 13, the horizontal and vertical structural elements 14 and 15, the stationary frame 16, and the sill 17. The sash portion 18 of the window may be hinged or otherwise rendered movable, if desired, and when the window is so constructed, the frame may be provided with a rigid upright member or mullion 19, against which the sashes may abut when the window is in closed position. As will be understood, the series of openings 20 defined by the horizontal and vertical structural elements of the windows, usually are closed by sheets or panes of glass or other translucent material. The structural elements of the window may be of metal or wood, in accordance with common practice. It will be understood, further, that a window need not incorporate sashes which are movable, although in most instances, a window will include movable sashes.

Fig. l of the drawings shows the air conditioning unit of the present invention partly extended through the window opening 20 from which a glass pane has been removed. When the installation is completed, the peripheral marginalportion 23 of the outer face 24 of a mounting panel 22, will flatly abut the inner coplanar faces of the several structural elements of the window which define the unglazed opening 20. It will therefore be understood that the unit when installed, will have its protective hood or casing 26 projected through the opening 20 and exposed to weather and the outside atmosphere, whereas the mounting panel 22 and the protective hood or casing 27 will be located interiorly of a room or compartment to be cooled. It may here be noted that the hood or casing 27 encloses the evaporator section of the air conditioning unit, whereas the exterior hood or casing 26 encloses the operating means or the compressor-condenser mechanism which operates to maintain a chilled condition of the evaporator.

From the foregoing, it will he understood that the mounting panel indicated generally at 22 includes opposite faces 24 and 25 properly identified as outer and inner faces, respectively. In practice, the outer margin of face 24 all around the panel maybe provided with suitable gasket material, not shown, in order to produce an air-tight and water-tight joint with the window elements defining the opening 20.

To preclude displacement of the unit relative to the opening 20 and the surrounding structural elements of the window, the mounting panel 22 near its two lower corners 28 maybe transversely drilledas at 29 to receive the threaded shank 30 of a fastening or securing means, which maybeinthe form of a rod threaded at one end to-receive ahand nut 31, whereas theother endis furnished-with a hook 32 extended outwardly of the panel face 12.4,toengage a structural elementof the window ing devices, abjovetdescribed, and tloeated near the lower corners of the mounting panel, suffice to maintain the entire unit in fixed relation to the window, due to the fact that the weight and disposition of the operating means within the hood 26 are such as to induce downward tilting of the exterior section of the unit about the lower edge of the panel acting as a fulcrum. Because of the tilting tendency mentioned, it is unnecessary to provide fastening devices or securing means at or near the upper edge of panel 22. From the foregoing it readily will be understood that installation of the air conditioning unit within a window opening such as 2%, can be completed within the space of a few minutes, whereas heretofore the installation procedure involved drilling, cutting and mutilation of the window sash or frame. When an air conditioning unit is installed in accordance with the present invention, it may easily and quickly be removed at any time, and the window may be restored to original condition by merely replacing the glass pane which previously had been removed from the opening 29.

Referring now to Figs. 3 to 6 of the drawings, the improved air conditioning unit will be seen to comprise an evaporator 34 enclosed within a housing 35 having an enlarged opening 36 to accommodate the blades of a fan 37 which is driven by an electric motor 38. The motor may be supported upon any suitable form of bracket element 39 fixed as at 40 to the base or bottom 41 of a pan indicated at 42. The evaporator housing may be furnished with a pair of wings 43 extending outwardly from opposite sides thereof, to substantially contact opposite end walls 45 of the evaporator hood 27, to control movement of air entering the hood through the grilles 46 and 47 and passing through the evaporator for discharge in a chilled condition by way of the outlet opening 48. The outlet opening may be furnished with a series of adjustable shutters or vanes 49, to control the angle or direction of chilled air discharged. A pair of outwardly extended flanges 50-50 at the rear of the evaporator housing, may be used as a means to support any appropriate form of filter or dust collector, not shown. Filters or dust collectors commonly employed in air conditioning units, are generally in the form of flat sheets or pads of loose fiber treated for the removal of dust and dirt particles moved therethrough by the action of fan 37.

It is important to note that pan 42 and all the elements above it including the evaporator, the fan or blower 37, and its bracket means 39, are supported from the inner face 25 of the mounting panel through the agency of a shelf-like support indicated generally by the reference character 51. be constituted of a pair of identical side brackets 52, each having an upright leg 53 and a horizontal leg 54 disposed substantially at right angles thereto. The upright legs 53-53 may be maintained in spaced parallelism by means of a connecting member or plate 54 welded or otherwise fixed thereto, the plate being in turn secured flatwise to the inner face 25 of the mounting panel by means of bolts, screws or other fastening devices 55 passing through holes 56 drilled in the mounting panel (Fig. 6). At 57 is shown a suitable flange member overhanging the plate 54, and providing a rest or support upon which may lie the upper rear edge portion 58 of the evaporator hood 27.

As illustrated upon Fig. 5, the pan 42 includes an upright partition wall 59, which in conjunction with the forward wall 60 and the side walls of the pan 42, forms a water-tight smaller pan or compartment 61 whose bottom is indicated at 62. The purpose of this pan or compartment 61 is to collect condensate from the evaporator 34, which latter is disposed directly above the pan 61. At the location 63, pan 61 is provided with a circular opening 63 to which is fitted a tube or other conduit means 64, which passes through an opening 65 in the mounting panel and delivers condensate from pan 61 to a location beyond the outer face 24 of the panel.

The shelf-like support may v The delivery end of the tube or conduit is indicated at 67.

Extending from the outer face 24 of mounting panel 22, is an exterior shelf-like support indicated generally at 68, which support includes a pair of spaced parallel upright legs bolted or otherwise secured to the outer face of the mounting panel. Extended outwardly from the pair of members 6) is a pair of spaced parallel legs 70, disposed substantially at right angles to the outer face 24 of the mounting panel. These legs are spanned by a sheet 71 welded or otherwise adjoined to the legs '70 in such manner as to form a water-tight pan, the outer end wall of which is indicated at 72. The sheet or pan bottom 71 may be furnished with a series of upstanding threaded studs 73, used as an acceptable form of means to mount the operating mechanism of the unit upon the exterior shelf-like support indicated generally at 70. Referring to Fig. 6, the characters 74 indicate holes formed in the mounting panel 22 to receive bolts or other fasteners which mount the exterior shelf-like support 70 upon the outer face of the mounting panel.

As indicated upon Fig. 3, the exterior shelf-like support carries the compressor 75, the condenser 76 enclosed within a suitable housing 77, a fan or blower "73 driven by a motor '79, and the incidental elements ordinarily constituting the operating mechanism for maintaining a chilled condition of the evaporator 34. In view of the fact that the operating mechanism for chilling the evaporator is common and well known in the art, it is deemed unnecessary and superfluous to burden the present disclosure therewith. It is important, however, to arrange the compressor, the fan and the condenser in tandem relationship as illustrated by Fig. 3, and to employ such elements with the proper dimensional limitations, to insure that the operating means as a Whole, along with the hood 26 therefor, may be passed through an opening 2d of any known size and style of casement window. The compressor indicated at of Fig. 3 is of the hermetically sealed type, and this form of compressor is preferred. In Fig. 6, the reference character 8t indicates an opening of the mounting panel, through which may be passed tubes or piping such as 81 which operatively connect the evaporator with the operating mechanism at the outer side of the panel.

Referring to Fig. 5, it will be noted that the bottom 62 of the condensate pan 61 is at a higher elevation than the bottom of pan 71. The purpose of this construction is to maintain a substantial level of water in the pan 71, While at the same time keeping the condensate pan 61 free of water at all times. As previously pointed out, the tube or conduit means 64 establishes the necessary connection between the pans 61 and 71. In the preferred form of the invention, the condenser fan will be of the general character indicated at 82 of Fig. 4, wherein the outer edges 83 of the blades 84 are provided with means for lifting condensate from the pan 71 and directing same through the coil structure of the condenser. Such lifting means may be in the form of a circular ring 85 attached to the ends of the fan blades, so that as the fan is driven by means of the motor 79, condensate continuously lifted and thrown by the ring 85 will be picked up by the blast of air from the fan blades, and directed forcefully through the coil structure of the condenser. In this way, the exterior pan 71 may be continuously cleared of condensate, while at the same time the cooling function of the condenser is enhanced, and water of condensation from the evaporator is virtually eliminated from the room in which the evaporator is located. It will be readily understood that unless the exterior pan 71 is disposed at a lower elevation than the condensate pan 61 beneath the evaporator, the water of condensation cannot be effectively kept drained from the pan 61 and disposed of in the manner described. The lifting ring 85, of course, must operate in close proximity with the bottom of the pan 71 near the entrance side of the condenser. The con densate lifted from the pan 71 and directed through the condenser coil emerges in mixed vapor and mist form. Aswill be understood, the ends 86 and 37 of the housings 77 and 26 are open to atmosphere outside the room. Cooling air for the compressor and condenser may be admitted to the interior of hood 26 by way of the grille 88, which may be duplicated at opposite sides of the hood if desired.

In order to provide for the delivery of atmospheric outside air into the room in which the evaporator section of the unit is located, an enlarged aperture 9%) may be formed in the mounting panel, placing the evaporator section in communication with the compressor section of the unit. This is most clearly illustrated upon Figs. 5 and 6. To control the volume of outside air admitted, a suitable valve or shutter for the aperture is provided. The valve or shutter may be in the form of a flat plate 91 movable across the aperture by means of a handle'92, which handle preferably is accessible only by removal of the hood 27. The valve or shutter may be mounted shiftably upon the panel as shown, bymeans of a pin or other form of pivot 93, or if desired, it may have slidable shiftability in any known manner. Aperture 90 may be provided with a screen, not shown, to exclude insects and the like. In order that the incoming air may not be drawn primarily from the compressor section, an angular bafile plate 94 may be applied to the outer face 24 of the panel, directed toward one of the side grilles 88, so as to induce flow of outside air through said grille and into the aperture 290, under the sucking of evaporator fan 37.

Indicated at95 upon Figs. 1, 2 and 3, is the control knob for an electric switch 96, whereby may be controlled the operation of the compressor and the fan or blower motors 38 and 79. The switch may be so wired to these elements, as to enable operation of the evaporator fan motor 38 independently of the compressor and the condenser fan motor 79. This arrangement is C0111. mon practice, and is well within the skill of the artisan, wherefore no detail disclosure of the wiring scheme is believed necessary.

The modified form of air conditioning unit illustrated by Figures 7 to 11, is in many respects similar to the unit heretofore described, and illustrated upon Figures 1 we, of the drawings. The principal distinction between the two units, resides in the provision of two exterior housing sections for the operating mechanism, as indicated at 98 and 99 upon Figs. 7 and .10. With the use of two exterior sections, it is possible toremploy larger and more powerful operating means to chill the evaporator of the unit, while at the same time retaining the advantageof compactness, and easy application of .the air conditioning unit to casement windows without drilling, altering or mutilating the structural elements of the window. Thus, in the modified form of the device,.the section 98 may be reserved forhousing the compressorltlt) and its appurtenances, while'the remaining section 99 houses the condenser 101 and the condenser fan .102 driven by the electric motor 103. The evaporator section, whose protective hood isindicated at 104,:houses'the evaporator coil 105, the evaporatoivfan 106, and the fan motor 107. As in =the case of the unit previously described, the elements of theevaporator section may be mounted upon a shelflike support similarzto that shown at 52 upon Fig. 3, and is to -include an evaporator pan to receive condensate during operation of the unit, such pan being viously described herein, the evaporator 105, condensate pan 108, and the fan or blower assembly 106-107, are hung or supported from the inner face 113 of the mounting panel, using an interior shelf-like support or bracket means corresponding to 52 of Fig. 3. The exterior sections or housings 98 and 99 may be hung or supported from the outer face 114 of the mounting panel, using exterior shelf-like supports or bracket meansas indicated generally at 115 of Fig. 11. The use of shelflilce supports or bracket means as described, facilitates assembly of the unit or dismantling thereof when necessary.

The unit of Figs. 7 to 11 is designed especially for application to a casement window in which, as illustrated by Fig. 8, two adjacent window openings 20-20 have their panes removed to accommodate the spaced parallel exterior sections 98 and 99 of the air conditioning unit. Such a window ordinarily includes a fixed upright structural element, or mullion 19, against which. may close and abut, the movable or hinged casement sashes at opposite sides thereof. The mullion ordinarily is part of the stationary frame of the window, and this part of the window at the least, is saved from mutilation or destruction in application of the Fig. 7 unit to the window. This is so, because of the fact that the unit with the spaced exterior sections 98 and 99 straddles the mullion in extending through the openings 20-20 to the outside of the room. As will be understood, the peripheral margin of the outer face 114 of the mounting panel abuts the mullion and the structural elements of the sash defining the openings 2020. In making the installation, suitable gasketing may be employed where the panel so abuts the window elements, to ensure a tight joint. The panel may be drilled transversely near the two lower corners thereof, as at 116 of Fig. .1, to accommodate fastening or securing means 117 which hold the panel against the window elements in precisely the same manner as was explained in the description of the fasteners 30 of Figs. 1 to 6. The weight at the exterior side of the mounting panel exceeds the weight at the interior side, and tends to tilt the exterior housing sections downwardly when the unit is in place upon the window.

Since in some casement windows the mullion 19 may vary in width, means are provided for increasing or decreasing the space 118 between the exterior housing sections 98 and 99. For this purpose, the shelf-like support of at least one of the exterior sections may be mounted for limited shiftability upon the outer face of the mounting panel, toward and from the other exterior section. Thus, the upright legs 119 and 126 of support 115 may be furnished with elongated horizontal slots 121 through which the several anchor bolts or fasteners 122 may pass. Since the upright legs and the horizontal outwardly extended legs 123 are connected, as by means of a plate 124 or otherwise, the brackets 125 and 126 constituted of the several legs mentioned, may be shifted in unison when the bolts orfasteners 122 are loosened, to vary the space between the two exterior sections 98 and 99, for accommodating mullions differently dimensioned and situated.

The condenser 101 and the motor driven fan 102 may be fixedly mounted upon the plate or bottom member 124 in any suitable manner, and as will be evident from the drawings, the condensate tube or conduit 109 may dischar e onto the member124. Member 124 may be in pan form, if desired.

It mayhere be noted that shiftability' of the exterior section 93 as above explained, may require a limited amount of shifting of rigid parts or elements which necessarily pass through the mounting panel from the evaporator section. Wherever such elements pass through, as in the case of the insulated hot line 125, the panel may be appropriately slotted horizontally as at 126, to permit limited shifting of the parts. Such slots may normally be closed with the use of any suitable form of plastic putty,

gum, or other filled substance. The condensate tube or conduit 109, of course, may be stationary relative to the mounting panel. Wiring and capillary tubes that extend through the panel from the evaporator section to the exterior section 98, ordinarily are sufficiently flexible to be bent without injury upon shifting of the exterior section, thereby eliminating the need for elongated slots for such elements passing through the panel.

In Fig. 11, the broken lines 98 indicate the location of the compressor section upon the exterior face of the panel. The characters 127 and 128 (Figs. 10 and 7) indicate grilles which permit cooling air to circulate through the compressor and condenser sections. At the evaporator section, 129 (Fig. 7) indicates the entrance port for room air, which upon being chilled by the evaporator, emerges from port 139 and enters the room being conditioned. The port 130 may include shutters or baffles, adjustable if desired, to selectively direct chilled air from the port. An arrangement for entry of outside air into the room may be provided for, in the manner heretofore disclosed in the description of Figs. 1 to 6.

A highly important consideration in connection with the unit of Figs. 7 to 11, is the fact that the capacity of the unit may when necessary be increased, by incorporating in each of the exterior sections a complete compressor-condenser assembly like that of Fig. 3. The air conditioning unit so equipped with duplicate operating means, will just as well fit the window openings 26-413, and straddle an upright or mullion such as 19; and with larger evaporator area it may be used to cool rooms or compartments of considerable size. Moreover, the two separate and complete compressor-condenser assemblies may be operated independently of one another at times, particularly when the cooling demand is light. This form of double unit is to be considered definitely an important phase of the present invention, for which patent cover- 7 age is sought.

opening, said unit comprising an apertured mounting panel with an inner face and an outer face for disposition to a room interior and to outside atmosphere, respectively, at substantially the plane of the window, said panel having a marginal. area to substantially abut the structural elements of the window, an exterior shelf-like supt port fixed to the outer face of the panel for extension through the window opening, refrigeration means including a compressor mounted upon said support, a pan beneath the refrigeration means aforesaid, an interior shelflike support fixed to the inner face of the panel, an evaporator mounted upon said interior support and operatively connected to the refrigeration means aforesaid, a second pan located beneath the evaporator to receive condensate therefrom, said second pan being at an elevation above the pan first mentioned, to induce gravitation of condensate from the second pan to the first, and conduit means passing through the mounting panel aperture to convey condensate from the second pan to the first pan.

2. An air conditioning unit as specified in claim 1, in which is included a condenser disposed above the pan of the exterior support, and motor driven means to lift condensate from said pan and direct same onto the condenser.

3. An air conditioning unit as specified in claim 1, in which is included a condenser disposed above the pan of the exterior support, and motor driven means to displace condensate from said pan, said pan including a bottom upon which is disposed a series of fixed upstanding studs providing anchorages for the compressor, the condenser, and the motor driven means aforesaid.

8 4. An air conditioning unit for application to a case ment window having a pair of unglazed lights separated by a. mullion, said unit comprising a mounting panel having a marginal area to substantially abut the structural elements of the window, a pair of spaced exterior shelflike supports adapted to extend through adjacent ones of said unglazed window lights in straddling relation to the mullion of the window, anchor means for each shelflilre support securing said supports to one face of the mounting panel in spaced relation, adjustment means cooperating with at least one of said anchor means and a support secured thereby, for varying the distance between the spaced supports at said one face of the mounting panel, an evaporator mounted upon the other face of the mounting panel, and means carried by at least one of the exterior shelf-like supports to maintain a chilled condition of the evaporator.

5. An air conditioning unit for application to a casement window having a pair of unglazed lights separated by a mullion, said unit comprising an apertured mounting panel with an inner face and an outer face for disposition to a room interior and to outside atmosphere, respectively, at substantially the plane of the window, said panel having a marginal area to substantially abut structural elements of the window, a pair of spaced exterior shelf-like supports adapted to extend through adjacent ones of said unglazed window lights in straddling relation to the mullion of the window, one of said shelflike supports including a bottom pan normally disposed substantially horizontally, anchor means for each shelflike support securing said supports to the outer face of the mounting panel in spaced relation, adjustment means cooperating with at least one of said anchor means and a support secured thereby, for varying the distance between the spaced supports at said outer face of the mounting panel, an evaporator mounted adjacent to the inner face of the mounting panel, a pan located beneath the evaporator to receive condensate therefrom, means mounting said pan beneath the evaporator with the bottom of the pan at an elevation above the plane of the pan first mentioned, means passing through the mounting panel aperture to convey condensate from the pan beneath the evaporator to the first mentioned pan, and means carried by at least one of the exterior shelf-like supports to maintain a chilled condition of the evaporator.

6. An air conditioning unit for application to a casement window having a pair of unglazed lights separated by a mullion, said unit comprising an apertured mounting panel with an inner face and an outer face for disposition to a room interior and to outside atmosphere, respectively, at substantially the plane of the window, said panel having a marginal area to substantially abut structural elements of the window, a pair of spaced exterior shelf-like supports adapted to extend through adjacent ones of said unglazed window lights in straddling relation to the mullion of the window, anchor means for each shelf-like support securing said supports to the outer face of the mounting panel in spaced relation, adjustment means cooperating with at least one of said anchor means and a support secured thereby, for varying the distance between the spaced supports at said outer face of the mounting panel, an evaporator mounted adjacent to the inner face of the mounting panel, a pan located beneath the evaporator to receive condensate therefrom, conduit means passing through the mounting panel aperture to convey condensate from said pan to a location beyond the outer face of the mounting panel, and means carried by at least one of the exterior shelf-like supports to maintain a chilled condition of the evaporator.

7. An air conditioning unit for mounting upon a window having rigid coplanar structural elements defining an opening, said unit comprising a mounting panel with an inner face and an outer face for disposition to a room interior and to outside atmosphere, respectively, at substantially the plane of the window, said panel having a marginal area to substantially abut the structural elements of the window, an exterior shelf-like support fixed to the outer face of the panel for extension through the window opening, a condenser mounted upon said support, a pan beneath the condenser, an interior shelf-like support fixed to the inner face of the panel, an evaporator mounted upon said interior .support, a second pan located beneath the evaporator to receive condensate therefrom, conduit means connecting the pans to convey condensate from the second pan to the first pan, and operating means including a compressor carried by one of said shelf-like supports, to maintain a chilled condition of the evaporator.

8. An air conditioning unit for mounting upon a window having rigid coplanar structural elements defining an opening, said unit comprising a mounting panel with an inner face and an outer face for disposition to a room interior and to outside atmosphere, respectively, at substantially the plane of the window, said panel having a marginal area to substantially abut the structural elements of the window, an exterior shelf-like support fixed to the outer face of the panel for extension through the window opening, a condenser mounted upon said support, an interior shelf-like support fixed to the inner face of the panel, an evaporator mounted upon said interior support, and operating means including a compressor carried by one of said shelf-like supports, to maintain a chilled condition of the evaporator.

References Cited in the file of this patent UNITED STATES PATENTS 2,322,904 Williams June 29, 1943 2,359,051 Roper Sept. 26, 1944 2,472,792 Cohler June 14, 1949 2,485,733 Hart Oct. 25, 1949 2,610,483 Deering Sept. 16, 1952 2,612,098 Bolin Sept. 30, 1952 2,654,233 Shoemaker Oct. 6, 1953 

